Insulated electrical connection



CONNECTION ECA INV ENTOR ATTORNEY J. V. POLK Filed April 7, 1934 NSULATED ELECTR May 7, 1935.

amavis nrsumrnn amorcer. coo'rron .lames V. Polk, :w1-w Tex., gnor to Geophysical Service Inc., a corporation of New Jersey pplioation April. 7, 1934, Serial No. 719,493

'ya all; i.

This invention relates to new and useful improvements in insulated electrical connections and it has particular reference to such connections in rotary drill pipes of the type employed especially in drilling wells.

The principal object of the invention isto provide means to eifect connection between the joints of drill stems., or pipes containing an electrical conductor whereby to avoid the diiilculties encountered heretofore when it became necessary to disconnect the joints of the drill stem in a, well. The present invention maintains a suitably insulated electrical conductor within the drill pipe and is so adapted that the electrical conductor is automatically broken atvthe joints when the drill pipe is disassembled and likewise, automatically reconnected when the l drill pipe is reassembled.

l invention shown The present invention has general application in any operation where it is necessary to have an electrical conductor pass through a drill pipe in rotation and it has specic application to the method described in the U. S. Patent No. 1,927,664. i

With the foregoing objects as paramount, the invention has particular reference to its salient features of construction and arrangement of parts which will become manifest as the description proceeds, taken in connection with the accompanying drawing, wherein:-

Figure l is a vertical section of a rotary table and drill stem assembly similar to that illustrated in U. S. Patent No.'1,927,664 incorporating the improvements herein defined. y

Figure 2 shows adjacent ends of a rotary drill pipe in fragmentary cross section embodying the present invention. a

Figure 3 is ja modied form of the present f ragmentarily in vertical cross section, and

Figure4 is a view on lines don Figure 3.

In Figure 1, the drill stem is designated by the A character I which extends tothe bottom of the holeand' to whic'lrisscured a drill bit 2. At the surfacegthe conventional rotary table is designated: at 3 through which passes the conventional Kellyjoint 4f. Connected to the upper l' end of the drill stema'sse'nibly is the conven- .tional water swivelfvslip ring 6 insures continuous .contactV between 4the battery 'I 'and the tubular conductors I2 in drill stem I so that an electric current may be caused to pass from the` battery 1, through the tubular conductor I2 to the drill bit 2. The electric current then ows into the earth around vtime bit 2, through (Cl. Z55-28) a. low resistance ground connection 8 through the ammeter 9 back to the battery l.

If the voltage across the battery 'l is substantially constant, such as will be the case provided the battery of suiciently large capacity and 5 as will be indicatedV by a voltmeter lll, the amount of current iiowing from the bit into the ground will be determined by the resistance of the ground near the bit, because the greater portion of the' electrical resistance in the circuit will be( in the vicinity of the bit 2. 'I'his is clearly described in the aforesaid Letters Patent No. 1,927,664.

Referring now particularly to the Apresent invention, it will be observed in Figure 2 that the ends of the drill stem sections are joined together by tapered threads II. Within the sections of drill stem I there is provided tubular conductors I 2 which are insulated from the inner walls of the drill pipe by the insulating liners I 3, which may be madeV of synthetic resin, varnished cambric, asphaltum or other suitable ma: terial. In order to compensate for any variation in the threads, theends of the sections of insulating material I3 are telescopically related, that is to say, the end of one section is reduced to receive the end of an'adjacent section as shown atainFigureZ.

Due to a certain amount of wear on the threads, slippage at the threads when the pipe is rotating and because of .irregularities in the length of the sections in a large-number of sections of vdrill pipe, it is necessary to provide an electrical contact at the joint in the pipe and which will be automatically adjustable to compensate for wear and variation in length, as Well as tobe free from slippage while the drill pipe is rotating to prevent disruption. of the electrical circuit. An electrical contact at the joint such as shown in Figure 2 very satisfactorily overcomes the conditions above described and may be comprised of a coiled spring` I4 which abuts the adjacent ends ofthe inner tubular conductor I2. This spring maybe made of bronze which has beenfound to be `a Vsuitable material.

Referring now to Figure a modified example 2-45 of the invention is. shown inthis igure and isl comprised vprimarily `of \a v.metallic sleeveV I5 :which is in sections, being divided into upper and Vlower sections at vb atlwhich `point is also, the

separating linebetween the drill stem sections I6 which are joined together by *theV taperedv lthreads II asin thepreceding case.

ing liner I9. It is understood that in screwing the sections of drill stem together, the sections of insulating material I8 and I9 must be capable of independent rotation, yet the electrical circuit through the joint must not be disrupted. In associating the insulated sections I8 and I9, an annular recess 20 is left intermediate the ends of the sections and in which is disposed metallic rings 2I and 22. A coiled spring 23 is interposed between the rings 2l and 22 and serves to maintain continuous electrical connection between the ends of the conductors through which current is passed through the drill stem assembly and to which reference will be made presently.

A metallic wire or rod 24, preferably of copper, is surrounded by an insulated covering 25 and through the medium of a tubular sheath 26, providing further protection, the conductor thus provided is secured into the upper section of the sleeve I5. As apparent, the wire or rod 2li continues downward into the insulating liner I 8 to the metallic ring 2| to which it is connected. Similarly, an electrical conductor in the form of a wire or rod 21, suitably covered by an insulating material 28, is secured by means of the sheath 29 to the lower section of the sleeve I5. Theconductor 21 continues into the lower section of the insulating liner I9 and is connected to the metallic ring 22 companion to the ring 2i.

It is apparent from the foregoing that when it is required to dismantle the drill stem assembly the electrical connection at the joints will not be disturbed since the upper section of the sleeve I is in fixed relation Ato the upper drill stem section and the insulating liner I8 rotates therewith.

When the drill stem sections are separated, there are no projecting elements which are likely to be injured by theV rough handling to which the drill stem is usually subjected. Accordingly, it is readily seen that by the use of the present invention, a completely connected conductor running the entire length of the drill stem assembly is obtained.

In order that the insulating liner I3, as shown in Figure 1, will not be subjected to any strain or other detrimental eiects resulting from the rotation of the drill stem assembly at the point where the drill bit 2 is joined thereto, the insulating liner is increased in diameter at its lower end as indicated by the character c so as to form a shoulder d against which the lower end of the drill stem abuts. The enlarged portion c of the liner I3 is both interiorly and exteriorly threaded. The inner threads jointly embrace the lower extremity of the conductor I2 andthe threaded pin 30 of the bit 2. A threaded connection 3| embraces the lower end of the drill stem and the internally threaded portion of the insulating liner I3. This is borne out in the lower portion of Figure 1. This arrangement maintains solid relationship between the bit 2 and the drill stem yet insures positive insulation between the metallic parts of the assembly and the bit.

Manifestly, the construction shown is capable of some modification and such modification as is considered within the scope and meaning of the appended claims is also considered within the spirit and intent of the invention.

What is claimed is: l. In combination with a rotary drill pipe assembly, means for making an electrical connection between two sections of said drill pipe assembly, conductors disposed within each section of sembly, means for making an electrical connection between the sections of said drill pipe comprising two conductors, each within a section of said rotary drill pipe and insulated therefrom, a pair of spaced rings to which said conductors are separately connected, a metallic coiled spring disposed between said rings and making connection with said sections of rotary drill pipe whenthe said sections are joined together, and means for insulating said metallic coiled spring from the said sections of drill pipe.

3. In combination with a rotary drillpipe assembly, means for making' an electrical connection between the sections of said drill pipe comprising two conductors, each within a section of rotary drill pipe and insulated therefrom, a pair of spaced metallic rings, one of which is electrically connected to each of said conductors, and a metallic coiled spring disposed between said rings whereby to make connection between said rings when the two sections of drill pipe are joined together, and means for insulating said rings and said metallic coiled spring from the said sections of drill pipe.

' 4. In a drill stem assembly, sections having diametrically opposed and insulated electrical conductors extending in parallel relationship therethrough and terminating short of their lengths, the end of one section being arranged to be received Within the end of an adjacent section whereby to bring adjacent'ends of said conductors into close proximity, a pair of spaced rings of conducting material between the ends of said sections and insulated resilient means disposed between said rings to effect electrical connection between said conductors.

5. 'In a drill stem assembly, drill stem sections having electrical conductors passing entirely therethrough and insulated from said sections and arranged to cause an electric current to flow progressively from one section to the other of said drill stem assembly, a pair of telescoping and independently rotatable insulating liners within said sections, a resilient electrical contact between the terminals of each of said conductors for compensating for relative movements of said sections at their junctures and means for insulating said contact from said sections.

6. In a. drill stem assembly, means for transmitting electric current progressively through the sections of said assembly, said means comprising` insulated electrical conductors disposed within each of said sections, relatively slidable and rotatable insulating sleeves in telescoping relationshipin each of said sections, and resilient means insulated from said sections by said sleeves for causing current to flow from one to the other of the conductors and to compensate for relative movements of said sections.

- JAMES V. POLK. 

